When the heart can’t deliver enough blood to the body and fluid consequently backs up into a dog’s lungs or abdomen, it’s called congestive heart failure. There are many causes of congestive heart failure (CHF) in dogs. CHF can be brought on by high blood pressure, congenital heart defects, heartworm disease, or a variety of other disorders. A dog with congestive heart failure may cough, have trouble breathing, experience fatigue, loss of appetite, or might die suddenly. Depending on the underlying cause, treatment can help reverse congestive heart failure, and medications are available to help relieve its symptoms.


Congestive heart failure is a broad medical term that means that a dog’s heart can’t deliver enough blood to his or her body. It can be caused by a failure of the left side, right side, or both sides of the heart.

When the heart starts to fail in its ability to pump enough blood, the body can usually compensate to ensure that tissues receive the blood and oxygen they need. As the disease increases in severity, these compensatory mechanisms become overwhelmed. The heart is then unable to pump enough blood to the body, so fluid backs up, most often into the lungs, causing congestion –– hence the term congestive heart failure.

Though many conditions can lead to congestive heart failure in dogs, one of the more common causes is chronic valve disease. When valves of the heart degenerate they may fail to function properly, leading to an increased burden on the heart and eventual CHF. Dilated cardiomyopathy is also a frequently observed cause of CHF in certain breeds of dogs. In this condition, the chambers of the heart become enlarged, which weakens the muscle walls so that they are unable to pump adequate amounts of blood to the body.

As a result of either disease, fluid may back up into the lungs, making breathing difficult, or into the abdomen, giving the dog a pot-bellied appearance.

Other causes of congestive heart failure in dogs include:

  • Defects in the heart walls
  • Fluid in the sac surrounding the heart
  • Heart rhythm abnormalities
  • Heartworm disease
  • Increased blood pressure
  • Endocarditis (an infection of the heart valves)
  • Tumors
  • Pregnancy
Congestive heart failure can occur at any age, in any breed, or in dogs of any gender, but it happens most often in middle-aged to older dogs.

Symptoms and Identification

In the early stages of congestive heart failure, your dog may show no signs at all. As the disease progresses, signs may include:

  • Coughing
  • Difficult or rapid breathing
  • Difficulty exercising
  • Weakness or lethargy (tiredness)
  • Fainting episodes
  • Gray or blue gums
  • Abdominal distention
  • Collapse
  • Sudden death
Congestive heart failure is usually diagnosed based on symptoms and physical examination findings, in which fluid in the lungs causes them to sound congested when your veterinarian listens with a stethoscope. To definitively diagnose the condition and determine its cause, veterinarians will usually recommend a number of tests, such as:

  • Blood and urine tests, including CBC, biochemical panel, heartworm test, and urinalysis
  • Chest radiographs (X-rays) to assess the heart, blood vessels, and lungs
  • An electrocardiogram (ECG)
  • An echocardiogram (an ultrasound exam to evaluate heart structure and function)
  • Blood pressure measurement
Referral to a veterinary cardiologist may be recommended.

Affected Breeds

All dog breeds may be affected by congestive heart failure, but Boxers, Doberman Pinschers, and Cocker Spaniels may be genetically predisposed to certain types of heart failure.


In some cases, such as congestive heart failure that is caused by heartworm disease, treatment of the underlying condition may resolve some or all of the heart problems. If the problem is caused by a congenital condition (a heart defect that the dog has had since birth), surgical repair may be an option. In most cases, however, the problem cannot be cured, but treatment can help improve dogs’ quality and length of life.

Dogs with severe congestive heart failure may require initial hospitalization and oxygen therapy. There are many medications that veterinarians may recommend to help reduce fluid buildup, improve heart function, and/or normalize heart rhythms. A low-sodium diet may also be recommended to help minimize fluid accumulation.

Most dogs with congestive heart failure require medications for the remainder of their lives. Periodic blood tests, radiographs, and echocardiograms are often needed to monitor treatment success and disease progression.


There is no known means of prevention of canine congestive heart failure except through judicious breeding programs designed to eliminate any hereditarily affected animals from the gene pool.

This article has been reviewed by a Veterinarian.